Sony STR-AV880 - Page 23

FM SECTION
FM Frequency Coverage Adjustment
Procedure:
Reading on
VOM
21 +0.2 V
8+0.5 V
Set
frequency
108 MHz
87.5 MHz
shield case
Adjustment
part
L105
Confirmation
C115 or VOM
(de range)
N L108 \. test point
STR-AV8&80
STR-AV880
FM Tracking Adjustment
This adjustment should be performed after finishing
FM Frequency Coverage Adjustment.
Setting:
FM rf signal
generator
ANTENNA REC OUT
FM (75Q)
Carrier frequency: 98 MHz
Modutation: 1 kHz, 75 kHz deviation
(100%)
Output level: less than 3.2 uV
(less than 10 dB)
1, Adjust L102, 103 for maximum reading on the
VTVM.
1 LIZ i103
| 7
7107
FM IF Adjustment
Setting:
distortion
meter
FM rf stereo
signal
generator
Hy /
iif om \i
| ef jouw
ANTENNA REC OUT
FM (75 Q)
Procedure:
1, Set the FM rf stereo signal generator as shown be-
low.
Carrier frequency: 98 MHz
Modulation: 1 kHz, 75 kHz deviation
(100%)
Output level: as low as passible
Mode: mono
2. Tune the set to 98 MHz.
3. Adjust the core of T101 for a maximum reading
on VIVM. ;
4. Set the FM rf stereo signal generator as shown be-
low.
Carrier frequency: 98 MHz
Output level: 1 mV (60 dB)
Modulation :
Audio 7 kHz: 33.75 kHz deviation {45%}
Sub channel 38 kHz: 33.78 kHz deviation (45%)
Pilot signal 19 kHz: 7.5 kHz deviation (10%)
Mode: stereo
5. Adjust the core of T101 for minimum distortion
near the maximum output level of REC OUT.
FM Discriminator Alignment
(NULL and MONO Distortion)
Setting:
FM rf stereo A :
signal distortion
generator meter
ANTENNA REC OUT
FM (75 9)
98 MHz
1 kHz, 75 kHz deviation
(100%)
1 mV (60 aB)
Carrier frequency:
Modulation:
Output level:
VOM
test point
(DC range)
(NULL CHECK)
Procedure:
. Tune the set to 98 MHz.
. Adjust T102 (primary-side) for 0 V reading on the
. Adjust T103 (secondary-side) for a minimum read-
ing on the distortion meter.
MONDO Distortion
. Repeat the primary-side and secondary-side align-
ments several times.
Note: When replacing the ceramic filter, perform this align-
ment.